Accepted name: exo-poly-α-digalacturonosidase
Reaction: [(1→4)-α-D-galacturonosyl]n + H2O = α-D-galacturonosyl-(1→4)-D-galacturonate + [(1→4)-α-D-galacturonosyl]n-2
Other name(s): pehX (gene name); poly(1,4-α-D-galactosiduronate) digalacturonohydrolase; exopolygalacturonosidase (misleading); poly[(1→4)-α-D-galactosiduronate] digalacturonohydrolase; exo-poly-α-galacturonosidase
Systematic name: poly[(1→4)-α-D-galactosiduronate] non-reducing-end-digalacturonohydrolase
Comments: The enzyme, characterized from bacteria, hydrolyses the second α-1,4-glycosidic bond from the non-reducing end of polygalacturonate, releasing digalacturonate.
1.  Hasegawa, H. and Nagel, C.W. Isolation of an oligogalacturonate hydrolase from a Bacillus species. Arch. Biochem. Biophys. 124 (1968) 513–520. [PMID: 5661621]
2.  Hatanaka, C. and Ozawa, J. Enzymic degradation of pectic acid. XIII. New exopolygalacturonase producing digalacturonic acid from pectic acid. J. Agric. Chem. Soc. Jpn.. 43 (1968) 764–772.
3.  Hatanaka, C. and Ozawa, J. Ber. des O'Hara Inst. 15 (1971) 47.
4.  He, S.Y. and Collmer, A. Molecular cloning, nucleotide sequence, and marker exchange mutagenesis of the exo-poly-α-D-galacturonosidase-encoding pehX gene of Erwinia chrysanthemi EC16. J. Bacteriol. 172 (1990) 4988–4995. [PMID: 2168372]
[EC created 1972, modified 2019]